While centreless grinding techniques have been used heretofore for the grinding of valves, for example of the kind used in the automobile industry, these prior uses have suffered from various drawbacks which it is an aspect of this invention to overcome.
Among the prior art considered in connection with this application are the following:
U.S. Pat. No. 1,533,133 Nickau, issued Apr. 14, 1925.
U.S. Pat. No. 1,452,508, Hervig, issued Apr. 24, 1923.
The drawbacks of the prior art relate to a lack of flexibility in the design, and to certain specific failings which will become clearer in the light of the following disclosure.